This invention generally relates to cathodes for cathode ray tubes and more particularly to fast warm up cathodes therefor. The fast warm up cathodes are designed to provide a warm up time of between four and six seconds. This warm up time is to achieve sufficient electron flow capability from the cathode to provide a viewable raster on the screen of a cathode ray tube.
Prior art cathodes of this type have been fabricated as two-part elements. A first element comprises a substantially cupshaped top cap, the closed end of which would be provided with an electron emissive material. A sleeve portion which is hollow and cylindrical and generally elongated in comparison to the length of the top cap has been provided with cut-out portions providing tabs which provide a minimum area contact means for attachment to the top cap. The top cap and the sleeve have been fabricated from relatively thin material; that is in the area of 3 to 6 thousandths of an inch thick. Problems have arisen in the manufacture of this type of cathode because of the flimsiness of the attachment portions formed in the cathode sleeve. It has been extremely difficult to mass produce these cathodes in any given quantity. Accordingly, it would be an advance in the art if a suitable cathode of this general description could be provided that had greater rigidity and greater ease of fabrication.